void floodFill4 (int x, int y, int fillColor, int interiorColor)
{
int color;

/* Set current color to fillColor, then perform following operations. */
	getPixel (x, y, color);
	if (color = interiorColor) 
	{
		setPixel (x, y);    			// Set color of pixel to fillColor.
		floodFill4 (x + 1, y, fillColor, interiorColor);
		floodFill4 (x - 1, y, fillColor, interiorColor);
		floodFill4 (x, y + 1, fillColor, interiorColor);
		floodFill4 (x, y - 1, fillColor, interiorColor)
	}
}